This report presents a macroeconomic analysis of two distinct situations: the Australian aviation industry and the French economic policies. Part A examines the Australian aviation industry, focusing on economies of scale and the market structure in 2002-03, identifying it as a duopoly. Part B analyzes the French macroeconomic policies, including the business cycle, depiction of growth using the AS-AD model, factors of growth, and the impact of long-term infrastructure investments. The analysis references GDP growth rates, business cycle diagrams, and the effects of government spending on infrastructure and education. The report concludes that investments in infrastructure and education can stimulate economic growth in the long run, as illustrated through aggregate demand and supply models.